Platen press for processing sheet material

ABSTRACT

A PLATEN PRESS HAVING BEDS WITH PLATEN SURFACES WHICH ARE PERIODICALLY OPENED AND CLOSED TO OPERATE ON A SHEET TRANSPORTED THEREBETWEEN IN A WORKING POSITION BY GRIPPING BARS DRIVEN BY AN ENDLESS CHAIN. THE GRIPPING BARS ENGAGE THE SHEETS AT A GRIPPING STATION AND TRANSPORT THE SHEETS TO THE WORKING POSITION BETWEEN THE PLATEN SURFACES. A RAIL WHICH HOLDS THE CHAIN TAUT PERIODICALLY MOVES IN SYNCHRONISM WITH THE BEDS AND SLACKENS THE CHAIN WHEN A BAR REACHES THE GRIPPING STATION WHEREUPON THE BAR IS ENGAGED AT BOTH ENDS BY POSITIONING MEMBERS WHICH ACCURATELY CONSTRAIN THE BAR TO OCCUPY A PREDETERMINED POSITION AT THE GRIPPING STATION.

F. LAUFER ETAI- PLATEN PRESS FOR PROCESSING SHEET MATERIAL Sept. 21, 1971 Filed July 5, 1968 3 Sheets-Sheet 1 PRIOR ART Sept. 21, 1 971 F. LA'UFE -R TAL 3,606,832

I PLATEN PRESS FOR YRQCESSING SEEET MATERIAL Filed July 5. 1968 3 Sheets-Sheet Sept. 21, 1971 LAUFER EI' AL I 3,606,832

PLATEN PRESS FOR PROCESSING SHEET MATERIAL Filed July 5. 1968 3 Sheets-Sheet 3 h. g 2 M I s g a a I0 I) F) g United States Patent US. Cl. 100215 10 Claims ABSTRACT OF THE DISCLOSURE A platen press having beds with platen surfaces which are periodically opened and closed to operate on a sheet transported therebetween in a working posltion by gripping bars driven by an endless chain. The gripping bars engage the sheets at a gripping station and transport the sheets to the working position between the platen surfaces. A rail which holds the chain taut periodically moves in synchronism with the beds and slackens the chain when a bar reaches the gripping station whereupon the bar is engaged at both ends by positioning members which accurately constrain the bar to occupy a predetermined position at the gripping station.

BRIEF SUMMARY OF THE INVENTION The present invention relates to a platen press for processing sheet material, such as paper or cardboard, of the type in which the sheets are conveyed by gripping bars advanced by two endless chains, alternatively driven and halted to bring the sheets to a working station, such as a sheet grasping station, followed by a processing station where the sheet lies between the platens which are to operate thereon.

At each station, the sheet must be fed to an exactly determined position.

An object of the invention is to provide an improved arrangement for halting the bars at the sheet grasping or gripping station.

In accordance with the invention, there is provided a displaceable rail in the region of the gripping statlon which engages the chains to hold the same taut, a means for periodically releasing the rail to slacken the chains when a bar carried thereby is in the proximity of the gripping station, and a pair of retractable members which are moved to operative position when the chains are slackened, to engage the ends of the bar and position the bar in an exact predetermined location at the gripping station.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic illustration of a conventional platen press and its arrangement for the feeding of sheets,

FIG. 2 is a diagrammatic view on an enlarged scale of a portion of the press and the feed for the sheets accord ing to the invention,

FIG. 3 shows in greater detail, and on further enlarged scale, a part of the arrangement of FIG. 2.

FIG. 4 is a view, from behind, of a part of the driving mechanism of the rail, and

FIG. 5 is a graphical illustration showing the various movements of the elements of the press during a working cycle of the press.

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DETAILED DESCRIPTION FIG. 1 diagrammatically illustrates a conventional ar rangement and serves to explain the problems it poses, and in particular, those which will be resolved in accordance with the present invention.

The press in FIG. 1 comprises a fixed upper bed 1, the lower face of which forms the fixed upper platen and a movable lower bed 2, the upper face of which forms the lower platen. This lower bed is driven up and down periodically while the press is working, the platen bearing tools for performing various operations on sheets fed between the platens such as cutting, corrugating, and the like.

On either side of the upper bed 1, travel two chains 3 of a pair of endless chains. The chains 3 advance gripping bars 4, 5, 6, 7, 8 between them. The gripping bars operate to convey the sheets between the two platens each time the latter are in their spaced, idle position (i.e. the illustrated position). The chains are guided by pairs of chain wheels, two of which are represented by numerals 9 and 10, the pair of wheels 9 being periodically driven in the direction of the arrow 11.

Two positions of immobilization of the thus conveyed gripping bars are important, i.e., those occupied in the drawing by the bars 4 and 5.

In the position of the bars 4, the latter is prepared to receive, from the left in FIG. 1, a sheet to be processed. In the position of the bar 5, the bar holds a sheet to be processed between the two platens. These two positions must be very accurately determined.

To this end, at each working cycle, stops or tappets 12, 13 are introduced into the path of travel of the bars and the latter are arrested against these stops.

Various arrangements are known to realize halting of the bars against their respective stops.

The heretofore known solutions for halting the bar 4 in the gripping position of the sheets are relatively intricate and the present invention provides a simple and reliable solution.

As for the bar 5 in the so-called working position, it is generally brought into abutment with the stops 13 by imparting to the chains 3 a feed slightly greater than that necessary for the correct setting of the bar, the excess of the movement of the chains thus stretched being absorbed by springs 14 allowing a slight compensating displacement of the pair of chain wheels 10 at the rear of the press.

As to the determination of the precise position of the bar in the sheet gripping station (position 4), this is achieved according to the present invention by an arrangement wherein each end of the bar is periodically engaged by two members in predetermined position, clamping it in the manner of a vise, while the portion of each chain immediately preceding this station is brought in abutment against a rail, a backward movement of which gives rise to a momentary slackening of the said portion of the chain, each time a bar is seized by the aforementioned members.

This is achieved in accordance with the present invention in a manner which will become evident from a consideration of FIGS. 2-5. wherein elements which are unchanged from those of the conventional arrangement will be given the same designation as in FIG. 1.

In FIG. 2 are seen the beds 1 and 2 with their respective platen surfaces 1' and 2' and the chains 3 and the gripping bars 4-8.

Preceding the bar 4, in its sheet grasping position, a portion of each chain comes into contact with a guiding rail 15, normally fixed, but adapted to momentarily 3 oscillate in the direction of the arrow 16 around a pivot 17.

The pair of wheels driving the chains is no longer in immediate proximity of the sheet grasping station, such as in FIG. 1, but is disposed at 9', just before the rail relative to the advancing direction of the chains. Thus, the rail 15 is located between the pair of wheels 9 and the sheet grasping station and cooperates with a portion of chain located immediately before the said station.

At the said station, two members, schematically represented in FIG. 2 by arrows 18 and 19, are capable of being raised, so as to seize the bar 4 and compress it in the manner of a vice in a predetermined, adjustable position. This tightening will be carried out at each end of the bar, and very accurately fixes the position thereby.

Such a setting of the bar would of course not take place in opposition to the tension of the chains. This is the reason for the presence of the rails 15 which by oscillating, at the moment of engagement of the members 18, 19, in the direction of the arrow 16, releases the chains which in this manner are momentarily slackened and make it possible for the members 18 and 19 to center the bar.

The assembly, when making reference also to FIG. 1, will work in such a way that in each. working cycle, a turn of the driving wheels 9' will cause the chains 3 to be fed by the amount necessary for the conveyance of a sheet from the grasping position 4 to the working position 5, with a slight excess of tension, insuring the correct setting of the bar 5, according to the known operating arrangement described in connection with FIG. 1. At the same time, the rails 15, will be released by an appropriate mechanism, or displaced by the latter, to release the chains, whereas the members 18, 19 will simultaneously fix the position required by the bar 4. The latter then receives a sheet from the feeding table 20, while the platen 2' goes up, processes the previously conveyed sheet, then lowers. Thereafter, the same operating cycle starts again.

FIG. 3, to a larger scale, shows in detail the operation of rail 15 and the tightening members 18 and 19.

The rail 15 is pivoted at 17 and feeds the chain 3 along a guide 21 which faces it. The rail 15 terminates just before the first tightening member 18. In prolongation of the rail is an upper guide 22, also facing the aforementioned guide 21.

The tightening member 18 is pivoted at 23 and actuated by a stem or rod 24.

In the raised position shown, the two members 18, 19 are in the position for tightening the bar 4, represented diagrammatically by a portion of the chain line drawn with greater thickness. The chain is stopped and by coming slightly closer to each other, the jaws of the two members 18 and 19 will clamp the bar 4 and fix the desired position, whereas the rail 15 will move in the direction of the arrow 16.

Immediate before the chain starts moving again, the rail is returned to its working position and the tightening members 18 and 19 are retracted, so as to withdraw their jaws from the path of travel of the bar.

The stems 24 and 26 and the lever 25, as well as the bar 28 for the rail, control these motions under the action of cams (not illustrated) driven at the rate of one turn for each working cycle of the press (a cycle corresponding to the passage and centering of a bar).

Although the tightening members 18 and 19 are positively controlled in all their positions, the rail is not except for its return to its working position. This control, partly hidden in FIG. 3, is shown in detail, from the rear, in FIG. 4.

On an arbor 29, the rail 15 bears a roller 30, against which can rest the nose 31 of a lever 32, pivoted at 33. The free end of the lever, opposite the nose, supports a roller 34, against which is applied a shoulder 35 of the bar 28.

A displacement of that bar in the direction of the arrow 36 will cause the lever 32 to pivot around 33 in the sense tending to apply the nose 31 against the roller 30, i.e. to bring and keep the rail 15 in its working position. The geometry of the lever 32 shows that the nose 31 will be applied against the roller 30 with augmented force. This is necessary due to the very strong pressure exerted by the chain against the rail during its displacement in each working cycle.

When the bar 28 moves back and the shoulder occupies the dotted line position in FIG. 4, the lever 32 is released which makes it possible for the rail 15 to move in the direction of the arrow 16 (under the action of the tension in the chain) and to release and slacken the corresponding chain portion,

The travel of the released rail 16 may be limited by a stop or a spring, or the rail can be controlled positively between its two extreme positions, i.e., Working and slackening of the chain.

The diagram of FIG. 5 summarizes a working cycle of the press. The abscissa corresponds to a working cycle.

The curve 37 represents the movement of the chains or displacement of the bars, that is: immobility at 37a, acceleration at 37b, conveyance at practically constant maximum speed at 37c and slowing down until immobility at 37d.

The curve 38 refers to the slackening of the chains, the curve 39 to the control of the tightening members 18 and 19 and the curve 40 to the raising of the stop 13 of FIG. 1.

As shown, the slackening of the chains takes place at 38a, during the immobilization of the latter at 37a; the tightening members 18, 19 are actuated at this moment (curve 39a), while simultaneously, the aforementioned stop 13 is placed into the trajectory of the bar in working position (5 of FIG. 1), as corresponds to the position of the curve 30a.

What is claimed is:

1. In a press having platens which periodically open and close and operate on a sheet transported therebetween in a working position by gripping bars which are driven by an endless chain and engage sheets at a gripping station and transport the sheets to the working position, an improvement comprising means at said gripping station engaging said chains to hold the same taut, means for periodically releasing the latter means to slacken the chain when a bar carried thereby is in proximity with said gripping station, and means for contacting said bar at opposite ends thereof when the chain is relaxed to locate the bar in exact predetermined position at said gripping station.

2. An improvement as claimed in claim 1 wherein said means for contacting said bar at opposite ends thereof comprises a pair of displaceable members which engage the ends of the bar and move to predetermined positions to cause the bar to be exactly positioned at said gripping station.

3. An improvement as claimed in claim 2 wherein said means for holding the chain taut comprises a movable rail which has an operative position engaging the chain to hold the same taut.

4. An improvement as claimed in claim 3 comprising a driving means engaging the chain for advancing the same, said driving means being positioned before the rail relative to the direction of travel of the chain.

5. An improvement as claimed in claim 3 wherein said means which periodically releases the rail comprises a mechanism which acts on the rail to hold the same in a position in which the chain is taut and including means which releases the rail to allow the same to be displaced under the action of the tension in the chain whereby the chain slackens.

6. An improvement as claimed in claim 3 comprising means supporting said rail for pivoted movement between a first position in which the chain is held taut and a second position in which the chain is relaxed.

7. An improvement as claimed in claim 6 wherein said means supporting the rail is a pivot located at an end of the rail remote from the gripping station.

8. An improvement as claimed in claim 3 wherein said means for holding the chain taut further comprises a displaceable rod and a lever operatively engaged by said rod to transmit a multiplied force from said rod to said rail urging the rail to a position in which the chain is held taut.

9. An improvement as claimed in claim 2 wherein said displaceable members are Pivotally movable between operative positions in which they engage the bar at its ends,

and retractable positions in which they are moved out 5 of the path of travel of the bar.

10. An improvement as claimed in claim 1 comprising stop means adjacent said platens for being introduced into the path of the bar conveying a sheet to the working position to arrest said bar after a supplemental drive has been impacted to the chain, and elastic means acting on said chain in its path of travel after it leaves the platen to its reintroduction thereinto.

References Cited UNITED STATES PATENTS 2,258,880 10/1941 Bobst 100--215UX 2,829,890 4/1958 Kury etal 271 79 3,405,937 10/1968 Schoch "271-79 FOREIGN PATENTS 769,251 3/1957 Great Britain 100-215 905,156 9/1952 Great Britain 100 215 1,036,132 7/1966 Great Britain 271-79 BILLY J. WILHITE, Primary Examiner US. Cl. X.R. 27 1-79 

